It depends where you are located and how of good condition they're in. They look pretty good in the pics but seeing them in flesh is best. These can actually get more money than a Snap-On because they come up less often on the market. A Mac fan will jump on these over a S-O set.
In my neck of the woods, the bottom can sell for $300 alone and the Mid for a round $100+
I sold online a Snap On mid box from the 60's for $200+ship. Having said that I think $150 for the bottom and $50 for the top is very fair. Of course paying way less is better, $150 for both would be a great price. Do you need these, r u willing to pass on them to wait for something else that is cheaper?
Do the shelves have old school built in dividers? There usually are not as desirable/valuable as with drawers without them.
For $200, I think it could sell quickly, thats about the average price. These are not the old beat up snap-on boxes you see given away for $75, these are newer and better. This is cheaper than what you could get at Harbor Freight.
I hope my ramble helped